Knee protector



1.1 is a top perspective view of a knee protector;

1.2 is a left side view thereof;

1.3 is a front view thereof;

1.4 is a back view thereof;

1.5 is a top view thereof;

1.6 is a bottom view thereof; and,

1.7 is a cross section view taken thereof along line 1.7-1.7 of FIG. 1.5.

Portions of the knee protector shown in broken lines form no part of the claimed design. 

CLAIM The ornamental design for a knee protector, as shown and described. 